Aims: The senescence of alveolar epithelial type 2 (AT2) cells is implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Cigarette smoke (CS) is a strong risk factor for IPF and it is also a pro-senescent factor. Here we aimed to investigate whether and how CS induces AT2 cells senescence via a SIRT1/autophagy dependent pathway.